[flang-commits] [flang] [flang] Fix `getTypeSizeAndAlignment` for packed/tail-padded `RecordType` and `TRANSFER` gate (PR #220377)

[Daniel Chen via flang-commits]

================
@@ -102,4 +102,44 @@ func.func @small_temp_in_acc_parallel() {
   return
 }
 
+// Tail-padded record array: !fir.array<3x!fir.type<tpad{a:i32,b:i8}>>
+// Each element is 8 bytes (5 typed + 3 tail padding), total = 24 bytes.
+// getTypeSizeAndAlignment must return 8 per element so the pass computes the
+// correct total of 24 bytes.  With the default 64-byte threshold this
+// 24-byte temporary array is small and must be promoted to stack.
+// CHECK-LABEL: func.func @tail_padded_record_placement
+// CHECK: fir.alloca !fir.array<3x!fir.type<tpad{a:i32,b:i8}>>
+// CHECK-NOT: fir.allocmem
+func.func @tail_padded_record_placement() {
+  %0 = fir.allocmem !fir.array<3x!fir.type<tpad{a:i32,b:i8}>>
+  %c0 = arith.constant 0 : index
+  %v = arith.constant 0 : i32
+  %r = fir.convert %0 : (!fir.heap<!fir.array<3x!fir.type<tpad{a:i32,b:i8}>>>) -> !fir.ref<!fir.array<3x!fir.type<tpad{a:i32,b:i8}>>>
+  %e = fir.coordinate_of %r, %c0 : (!fir.ref<!fir.array<3x!fir.type<tpad{a:i32,b:i8}>>>, index) -> !fir.ref<!fir.type<tpad{a:i32,b:i8}>>
+  %f = fir.coordinate_of %e, %c0 : (!fir.ref<!fir.type<tpad{a:i32,b:i8}>>, index) -> !fir.ref<i32>
+  fir.store %v to %f : !fir.ref<i32>
+  fir.freemem %0 : !fir.heap<!fir.array<3x!fir.type<tpad{a:i32,b:i8}>>>
+  return
+}
+
+// Packed record array: !fir.array<3x!fir.type<tpk<{i:i32,d:f64}>>>
+// Each element is 12 bytes (packed: 4+8, no gaps or tail padding), total=36B.
+// getTypeSizeAndAlignment must return 12 per element (not 16) so the pass
+// computes the correct total of 36 bytes.  With the default 64-byte threshold
+// this 36-byte temporary array is small and must be promoted to stack.
+// CHECK-LABEL: func.func @packed_record_placement
+// CHECK: fir.alloca !fir.array<3x!fir.type<tpk<{i:i32,d:f64}>>>
+// CHECK-NOT: fir.allocmem
+func.func @packed_record_placement() {
+  %0 = fir.allocmem !fir.array<3x!fir.type<tpk<{i:i32,d:f64}>>>
----------------
DanielCChen wrote:

Fixed.

https://github.com/llvm/llvm-project/pull/220377